Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, Room 305 LSOG, 333 Cedar Street, PO Box 208063, New Haven, CT 06520-8063, USA.
Br J Cancer. 2010 Sep 7;103(6):812-9. doi: 10.1038/sj.bjc.6605760. Epub 2010 Aug 10.
Uterine serous papillary adenocarcinoma (USPC) is a highly aggressive variant of endometrial cancer. Human immuno-conjugate molecule (hI-con1) is an antibody-like molecule targeted against tissue factor (TF), composed of two human Factor VII (fVII) as the targeting domain, fused to human immunoglobulin (Ig) G1 Fc as an effector domain. We evaluated hI-con1 potential activity against primary chemotherapy-resistant USPC cell lines expressing different levels of TF.
A total of 16 formalin-fixed, paraffin-embedded USPC samples were evaluated by immunohistochemistry (IHC) for TF expression. Six primary USPC cell lines, half of which overexpress the epidermal growth factor type II (HER2/neu) receptor at 3+ levels, were assessed by flow cytometry and real-time PCR for TF expression. Sensitivity to hI-con1-dependent cell-mediated cytotoxicity (IDCC) was evaluated in 5-hour-chromium release assays. Finally, to investigate the effect of interleukin-2 (IL-2) on IDCC, 5-h (51)Cr assays were also conducted in the presence of low doses of IL-2 (i.e., 50-100 IU ml(-1)).
Cytoplasmic and/or membrane TF expression was observed in all 16 (100%) USPC samples tested by IHC, but not in normal endometrium. High expression of TF was found in 50% (three out of six) of the USPC cell lines tested by real-time PCR and flow cytometry when compared with normal endometrial cells (NECs; P<0.001). Uterine serous papillary adenocarcinoma cell lines overexpressing TF, regardless of their high or low HER2/neu expression, were highly sensitive to IDCC (mean killing+/-s.d., 65.6+/-3.7%, range 57.5-77.0%, P<0.001), although negligible cytotoxicity against USPC was seen in the absence of hI-con1 or in the presence of Rituximab control antibody. The addition of low doses of IL-2 further increased the cytotoxic effect induced by hI-con1 against chemotherapy-resistant USPC.
hI-con1 induces strong cytotoxicity against primary chemotherapy-resistant USPC cell lines overexpressing TF. The hI-con1 may represent a novel therapeutic agent for the treatment of patients harbouring advanced, recurrent and/or metastatic USPC refractory to standard treatment modalities.
子宫浆液性乳头状腺癌（USPC）是子宫内膜癌的一种高度侵袭性变体。人免疫缀合分子（hI-con1）是一种针对组织因子（TF）的抗体样分子，由两个作为靶向结构域的人因子 VII（fVII）组成，融合到人免疫球蛋白（Ig）G1 Fc 作为效应结构域。我们评估了 hI-con1 对表达不同水平 TF 的原发性化疗耐药 USPC 细胞系的潜在活性。
总共评估了 16 例福尔马林固定、石蜡包埋的 USPC 样本的 TF 表达情况，采用免疫组织化学（IHC）进行检测。通过流式细胞术和实时 PCR 评估 6 种原发性 USPC 细胞系的 TF 表达情况，其中一半细胞系过表达表皮生长因子受体 II 型（HER2/neu）受体，水平为 3+。在 5 小时铬释放测定中评估 hI-con1 依赖性细胞介导的细胞毒性（IDCC）的敏感性。最后，为了研究白细胞介素-2（IL-2）对 IDCC 的影响，还在低剂量 IL-2（即 50-100IU/ml）存在的情况下进行了 5 小时（51）Cr 测定。
通过 IHC 检测，所有 16 例（100%）USPC 样本均观察到细胞质和/或膜 TF 表达，但正常子宫内膜中未观察到。实时 PCR 和流式细胞术检测到，与正常子宫内膜细胞（NECs）相比，6 种 USPC 细胞系中有 50%（3/6）高表达 TF（P<0.001）。过表达 TF 的子宫内膜浆液性乳头状腺癌细胞系，无论其 HER2/neu 表达水平高低，对 IDCC 均高度敏感（平均杀伤+/-标准差，65.6+/-3.7%，范围 57.5-77.0%，P<0.001），尽管在不存在 hI-con1 或存在利妥昔单抗对照抗体的情况下，对 USPC 几乎没有细胞毒性。添加低剂量的 IL-2 进一步增加了 hI-con1 对化疗耐药 USPC 诱导的细胞毒性作用。
hI-con1 诱导对高表达 TF 的原发性化疗耐药 USPC 细胞系产生强烈的细胞毒性。hI-con1 可能成为治疗晚期、复发性和/或转移性 USPC 患者的一种新的治疗药物，这些患者对标准治疗方法耐药。
